Fatal Cokeromyces recurvatus pneumonia: report of a case highlighting the potential for histopathologic misdiagnosis as coccidioides.

Cokeromyces recurvatus is a dimorphic zygomycete with histologic morphology similar to Coccidioides immitis. A 66-year-old man who was status-post bone marrow transplantation for chronic myelogenous leukemia was hospitalized with new onset rash, nausea, and vomiting and subsequently expired. A sputum culture collected on the day of death revealed heavy growth of C. recurvatus 6 days after collection. At autopsy, microscopic examination of the lungs revealed numerous thick-walled, nonbudding spherules ranging in size from 40 to 80 µm. Initial immunohistochemical staining of the formalin-fixed lung tissue was positive for Coccidioides. Additional immunoperoxidase staining revealed the organisms were consistent with a zygomycete fungus, compatible with C. recurvatus infection. Polymerase chain reaction using panfungal primers was attempted on the formalin-fixed tissue but was inconclusive. This case highlights the potential for misdiagnosing Cokeromyces as Coccidioides when the diagnosis is based on histology and immunohistochemical staining.